Add some macros for concise tree builder actions
Replace Servo's namespace.rs with a stub
Relicense under the Rust licenses (ASLv2 and MIT)

Approved by me, and by Chris Morgan <me@chrismorgan.info> on 2014-05-23,
message ID CAMF4Wei114XdxWVb0jWaLXvrpzaA127aB7xjp66Hh_SW28GDpg@mail.gmail.com
Temporary upgrade to unreleased Rust
Rework whitespace splitting again

This is a bit more clear.
wip